Do not buy E85 !

[TiredTrucker]

Originally Posted By: oldhp
E85 can be anything from 51% to 83% ethanol. Worthless to me. If it's so good, why do my tax dollars still subsidize it?

Maybe your Illinois state taxes subsidizes some aspects of the ethanol thing, but all federal subsidies were eliminated at the end of 2011. There were some grants in recent years for retailers to install blender pumps that would offer various blends on ethanol gas combinations, but those were retailer grants, not ethanol subsidies.

 

[y_p_w]

Originally Posted By: Surestick
Originally Posted By: y_p_w
I've heard that since more fuel needs to be dumped in with E85, the tendency is to cool the mixture, which can make it slightly more efficient with respect to the actual energy content of the fuel.


The extra fuel should cool the incoming air somewhat (unless it's a GDI) which will increase volumetric efficiency a bit but the extra fuel also takes up some volume that could be used by extra air decreasing volumetric efficiency somewhat.

In a boosted engine where boost is limited by detonation that's less of an issue since the extra octane of the E85 means you can increase boost.

There's less energy content in the fuel though so fuel mileage is going to go down no matter what (unless you drive more slowly).


As was stated, the oxygen in the alcohol more than makes up for the tiny loss of O2 from air.

Of course the main reason why flex fuel engines are sold is because CAFE standards can be met easier based on the gasoline content of the fuel.

 

[blupupher]

E-85 around here is almost as much as Regular unleaded, but as mentioned, the fuel mileage hit is pretty big. It takes more fuel to travel the same distance, how is that good for the environment?

I don't have a flex fuel vehicle, but if I did and the price difference was big enough, I would not have a problem using e-85, there are plenty of stations around me that have it (my 2 primary stations have it).

 

[OPR4H]

The byproducts of combustion are less harmfull. A better burn, no fuligem and soot. That's environment friendly.

 

[B320i]

Sounds like E85 is a bit like converting one's car to LPG (as was rather popular in Australia until petrol prices dropped to their current levels). Fuel consumption penalty can be between 0% and 30%, depending on the vehicle and whether one goes with injection or a mixer/venturi system.

But, you get a higher octane fuel, potentially better performance, a much cheaper fuel and the emissions aren't as bad, despite the higher consumption.

 

[y_p_w]

Originally Posted By: B320i
Sounds like E85 is a bit like converting one's car to LPG (as was rather popular in Australia until petrol prices dropped to their current levels). Fuel consumption penalty can be between 0% and 30%, depending on the vehicle and whether one goes with injection or a mixer/venturi system.

But, you get a higher octane fuel, potentially better performance, a much cheaper fuel and the emissions aren't as bad, despite the higher consumption.

They're all "flex fuel" though, and done by the manufacturer. The main issue is seals that can handle the E85. Other than that it's just an adaptive ECU. Part of the reason why they're offered is because it gives automakers fuel economy credits for meeting corporate average fuel economy (CAFE) requirements. The basic premise is that they will be fueled 50/50 on E85 and gasoline. On E85, it's assumed that only the gasoline content counts as fuel consumed, so that provides a ridiculously high fuel economy rating for such vehicles.

The credits were supposed to go away though, but it's apparently been extended.

 

[Olas]

The octane level and the latent heat capacity of ethanol together are what give it so much potential, unfortunately without correct mapping none of its benefits can be realised.
Can you buy moonshine locally? Or brew it? Same stuff, only you can brew it for even higher octane!

 

[DriveHard]

Originally Posted By: TiredTrucker
Originally Posted By: oldhp
E85 can be anything from 51% to 83% ethanol. Worthless to me. If it's so good, why do my tax dollars still subsidize it?

Maybe your Illinois state taxes subsidizes some aspects of the ethanol thing, but all federal subsidies were eliminated at the end of 2011. There were some grants in recent years for retailers to install blender pumps that would offer various blends on ethanol gas combinations, but those were retailer grants, not ethanol subsidies.


Here in Iowa it is law that E85 has a minimum of 70% ethanol.

 

[DriveHard]

Originally Posted By: Olas
The octane level and the latent heat capacity of ethanol together are what give it so much potential, unfortunately without correct mapping none of its benefits can be realised.
Can you buy moonshine locally? Or brew it? Same stuff, only you can brew it for even higher octane!


Your first two points are correct. Your second, however, is not entirely correct. Yes, you will see more benefit with a smart engine controller that can take advantage of E85 from a timing perspective, but an SAE paper published in 2010 (#2010-01-0619) states that the mechanism of the charge cooling effect of E85 alone can increase engine efficiency and total power output. "The airflow for E85 increases about 2% compared to regular unleaded, and E50 air flow increases about 1.5% due to the charge cooling effect." So while a smart engine controller would be better, even if you don't have one with the ability to adapt to E85, you will still see a maximum power increase with E85 due to the charge cooling effect of both the increased mass flow rate of fuel required as well as the higher latent heat of vaporization of ethanol.

 

[OPR4H]

The speed flame on tipical engines cr are, for gasoline, about 22 to 25 mps, now ethanol is 30 to 33 mps. That's translates to powah.

 

[travlnman]

Well, long time no post. As promised I finally made it back to report on my findings, however insignificant they may be

If you will remember, I can only get E85 from a station over an hour away, and don't get a chance to use it all the time. My biggest question was, if you remember, was the power increase strictly due to higher octane, or was there more to it ? Since my absence, many of you have chimed in (thank you) and provided lots of great information, but I was curious to see if it all played out in real life. The power increase on the E85 was obvious, but what about running only 93 octane in it's place ? My truck has run nothing but 93 octane since I ran the last tank of E85. While the 93 did seem to run better than 87...it was nothing compared to the E85 increase. Throttle response was down, trans didn't shift as quickly, just no comparison. In the interim, I also changed all my coilpacks and new spark plugs to cure a slight misfire at 115k. Just within the last week, I've had the opportunity to fill up on E85 for 3 tanks in a row and lets just say, my truck is a different beast again and I like it. BTW, it was mentioned somewhere about varying amounts of alcohol, and I think I mentioned (maybe) that the location I purchase it from only states a minimum of 51% required. However, I have the Torque APP on my phone, and one of the realtime data displays available is the amount of ethanol present in my fuel. It typically shows my local 93 octane has between 7-9% . After three tanks of E85, it currently shows my ethanol content at 74%....and purring like a kitten. I appreciate all the information everyone shared, and I hope someone is helped out along the way. Like I said in the beginning, I have no interest in political debate, this was intended strictly to share my thoughts and opinions...your mileage may vary

 

[y_p_w]

Originally Posted By: travlnman
Well, long time no post. As promised I finally made it back to report on my findings, however insignificant they may be

If you will remember, I can only get E85 from a station over an hour away, and don't get a chance to use it all the time. My biggest question was, if you remember, was the power increase strictly due to higher octane, or was there more to it ? Since my absence, many of you have chimed in (thank you) and provided lots of great information, but I was curious to see if it all played out in real life. The power increase on the E85 was obvious, but what about running only 93 octane in it's place ? My truck has run nothing but 93 octane since I ran the last tank of E85. While the 93 did seem to run better than 87...it was nothing compared to the E85 increase. Throttle response was down, trans didn't shift as quickly, just no comparison. In the interim, I also changed all my coilpacks and new spark plugs to cure a slight misfire at 115k. Just within the last week, I've had the opportunity to fill up on E85 for 3 tanks in a row and lets just say, my truck is a different beast again and I like it. BTW, it was mentioned somewhere about varying amounts of alcohol, and I think I mentioned (maybe) that the location I purchase it from only states a minimum of 51% required. However, I have the Torque APP on my phone, and one of the realtime data displays available is the amount of ethanol present in my fuel. It typically shows my local 93 octane has between 7-9% . After three tanks of E85, it currently shows my ethanol content at 74%....and purring like a kitten. I appreciate all the information everyone shared, and I hope someone is helped out along the way. Like I said in the beginning, I have no interest in political debate, this was intended strictly to share my thoughts and opinions...your mileage may vary

There are differing claims about octane rating of ethanol and E85. I've heard of everything from a (R+M)/2 octane rating of 100 to 114 for ethanol. E85 may have an octane rating of anywhere from 94 to 105 depending on who you believe. However, it's an adaptive ECU, so it will advance the timing as much as possible, which improved efficiency and top-end power.

 

[mooferz]

Originally Posted By: y_p_w
There are differing claims about octane rating of ethanol and E85. I've heard of everything from a (R+M)/2 octane rating of 100 to 114 for ethanol. E85 may have an octane rating of anywhere from 94 to 105 depending on who you believe. However, it's an adaptive ECU, so it will advance the timing as much as possible, which improved efficiency and top-end power.

The way I've heard it explained is that E85 actually has an octane towards the lower end of that range, but the actual resistance to knock is higher than this octane rating suggests. The ASTM octane test procedures would need to be modified to assign E85 an anti-knock rating that is directly comparable to gasoline, so folks tend to ballpark it to 105 or so.

 

[OilSwag]

E85 for high power forced induction cars, only if you have a way to switch between tunes. It isn't readily available where I live.
93 pure for naturally aspirated cars unless your making gobs of power.

 

[SteveSRT8]

Mooferz has it right. E85 is far more resistant and not just due to raw octane.

All our trucks are flex fuel and run noticeably better on E85. Since we burn half our fuel in stationary operations fuel mileage is not a big concern here, but the incredibly improved power, response, and shifting is nice...

 

[y_p_w]

Originally Posted By: mooferz
Originally Posted By: y_p_w
There are differing claims about octane rating of ethanol and E85. I've heard of everything from a (R+M)/2 octane rating of 100 to 114 for ethanol. E85 may have an octane rating of anywhere from 94 to 105 depending on who you believe. However, it's an adaptive ECU, so it will advance the timing as much as possible, which improved efficiency and top-end power.

The way I've heard it explained is that E85 actually has an octane towards the lower end of that range, but the actual resistance to knock is higher than this octane rating suggests. The ASTM octane test procedures would need to be modified to assign E85 an anti-knock rating that is directly comparable to gasoline, so folks tend to ballpark it to 105 or so.

The octane rating is just a number, and frankly just a tool. In some markets the recommended octane rating is just RON (that's made for some interesting discussions about how Americans get "[censored] fuel" which doesn't tell the entire picture.

The really important thing is what happens in practice and not the number. The ECU will advance the timing until it reaches the onset of knock and keep it there. And with E85 it can advance the timing a ton.